• Tag : BGP

 
 

Bgp Monitoring Protocol for Multi-agent Model

Bgp Monitoring Protocol for Multi-agent Model Description BGP Monitoring Protocol (BMP) allows a monitoring station to connect to a router and collect all of the BGP announcements received from the router’s BGP peers. The announcements are sent to the station in the form of BMP Route Monitoring messages generated from path information in the router’s BGP Adj-Rib-In tables. A BMP speaker may choose to send either pre-policy routes, post-policy routes, or both. BMP functionality is available with the single agent routing protocol model since EOS-4.21.1F as described here.  EOS 4.21.4F introduces support for BMP in the multi-agent routing protocol model. Platform...
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Displaying Neighbors’ Names with OSPF and BGP

This article describes how to configure Arista devices to display user-defined names for OSPF and BGP neighbors. OSPF First define name to IP address mappings, one per neighbor, where IP address is neighbor’s OSPF router ID: SW1(config)# ip host SW2 2.2.2.2 Next enable OSPF name resolution: SW1(config)# ip ospf name-lookup Finally, validate the output of ‘show ip ospf neighbor’ command. The command should display the user-defined name instead of router-ID: SW1(config)# show ip ospf neighbor Neighbor ID   VRF         Pri       State             Dead Time     Address        Interface SW2   ...
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iBGP over VRF – Open Message Error/bad BGP ID

Hi all, I am trying to establish iBGP between 2 Arista devices in a VRF, and got this error: Peering failure hint: Open Message Error/bad BGP ID Do you what what does it mean? The current status is: DEFRA2-NDSW99#sh ip bgp nei vrf PSP BGP neighbor is 10.208.1.140, remote AS 65508, internal link BGP version 4, remote router ID 0.0.0.0, VRF PSP Failed connection attempts is 321 Idle-restart timer is inactive BGP state is Active Peering failure hint: Open Message Error/bad BGP ID Last sent notification:Open Message Error/bad BGP ID, Last time 00:01:48, First time 35d13h, Repeats 41026 Last rcvd...
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Enterprise Internet Routing

Overview The objective of this document is to cover the most common Enterprise Internet Routing use case. The information provided here is based on two Arista switches peering with two ISP’s (Internet Service Providers) for redundancy. There are many other valid deployment models that are not covered in this document. Terminology BGP – Border Gateway Protocol ISP – Internet Service Provider BGP Peering – a session between two BGP routers that allows exchange of routes Full Internet Routing Table – all public routes on the Internet AS – Autonomous System – defines domain boundaries IGP – Interior Gateway Protocol EGP...
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Identifying BGP aggregate contributors in outbound policy

Description This feature adds a new match clause for outbound route maps. The new match clause allows matching on 1) any BGP aggregate contributor or 2) a specific BGP aggregate’s contributor. Matching on BGP aggregate contributors allows for the selective application of attributes (such as communities) to said contributors; these attributes can then be used for identification and filtering purposes by neighbors. Currently this feature is supported in the ribd routing protocol model only. Configuration Match contributors to any aggregate To match contributors to any BGP aggregate and set attributes (say communities) on said contributor, add an outbound policy with the...
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RIB route control: next hop resolution policy

Description RIB Route Control is a collection of mechanisms for controlling how IP routing table entries get used. Next hop resolution policy adds support for preventing recursive resolution of next hops based on route map evaluation of resolving routes. Platform compatibility Next hop resolution policy is a platform independent feature. Configuration Next hop resolution policy is configured for a particular VRF with the rib ipv4|6 resolution policy command under router general. Arista(config)#router general Arista(config-router-general)#vrf default Arista(config-router-general-vrf-default)#rib ipv4 resolution policy MAP1 Dependant routes whose resolving route is permitted by the route map will be recursively resolved, and dependant routes whose resolving route is denied...
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Support for matching AS path length in BGP

Description The route map feature in BGP allows filtering and manipulating BGP path information. It combines set statements with matching on various path attributes, to make these set statements conditional. This feature provides ability to match on AS path length. Using this match statement, BGP path information could be modified or filtered based on the length of AS path associated with it. This feature is available with the multi-agent routing protocol model and the ribd routing protocol model. It is applicable to VRFs as well. The AS path may consist of different segments: AS_SET, AS_SEQUENCE, AS_CONFED_SEQUENCE, AS_CONFED_SET. For the purpose...
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ribd vs multi-agent (ArBGP)

My organization is developing lab scenarios to move our network towards implementing EVPN. Part of that process is to add the: service routing protocols model multi-agent command. We have found a few unique situations where the default behavior of routing (outside of BGP) has changed. For example: OSPF summary routes not working Static routes to unreachable next hops (while the interface is up) are not placed in the RIB. I have been unable to find any documentation outside about what actually changes when implementing that command. Is there a white paper about it, or a list of default behaviors that...
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MP_UNREACH_NLRI causing NOTIFICATION

We have a peering BGP session that keeps dropping. This is between two IPv6 peers. OPEN happens, capabilities are agreed open, and prefixes are exchanged via UPDATE messages. Then one of the peers sends an UPDATE with ORIGIN, AS_PATH, and MP_UNREACH_NLRI attributes, which should be a valid update, much like ORIGIN, AS_PATH, and MP_REACH_NLRI. However, the Arista complains about a missing well-known attribute, and the data field is set to “3”, which indicates that it’s apparently wanting to see NEXTHOP(3). Consequently we send them a NOTIFICATION and the session drops. Looking at the RFCs, this seems like a valid update...
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BGP Peering – Configuration Best Practices – Security and Manageability

      BGP Peering – Configuration Best Practices – – – – – – – – – – – – – – – – Security and Manageability       1) Introduction This article provides suggestions of BGP peering configuration, with general best practices and some particular considerations for manageability and security.     2) Arista EOS Security – General   It is recommended to approach security not only specifically for BGP but to englobe other aspects of security for Arista EOS. More global security topics are covered in other articles, listed below. The present article focuses solely on...
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ecmp bgp question

Here my scenario : sw1 sw2 ! ! ebgp ebgp ! ! servers x1 servers x2 Basically I have some servers which peer locally on each arista switchs. All the servers advertise some /32 (via bird), which I want to be equally distributed on each switch. router bgp 49477 router-id 193.169.66.2 graceful-restart restart-time 300 bgp always-compare-med maximum-paths 64 bgp listen range 193.169.66.96/27 peer-group prdinfcdn remote-as 65042 no bgp bestpath ecmp-fast neighbor ipv4-ibgp peer-group neighbor ipv4-ibgp remote-as 49477 neighbor ipv4-ibgp update-source Loopback0 neighbor ipv4-ibgp additional-paths receive neighbor ipv4-ibgp additional-paths send any neighbor ipv4-ibgp maximum-routes 12000 neighbor prdinfcdn peer-group neighbor prdinfcdn remote-as...
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BGP Conditional Route Inject (Routing protocol mode Rib)

Introduction BGP Conditional route inject provides the capability to control BGP advertisements based on certain conditions in the System. This is achieved using “Dynamic prefix-lists” policy type. Dynamic prefix-list policy construct is similar to the traditional IP and IPv6 prefix-list, except that they have an additional state associated. This state associated with the dynamic prefix-lists, is determined on the basis of the route entries in FIB, and hence as and when the FIB changes, the state also changes dynamically. This state determines the dynamic prefix-list behavior, when used in route-map match clauses etc. Dynamic prefix-list can be used to: 1. Conditionally advertise/withdraw set of...
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Carrying Label Information in BGP-4

Theory of BGP-LU Overview  MPLS typically has been used in core service provider (SP) networks. These deployments, however, have expanded beyond the network core and edge to the access and metropolitan networks. This rapid growth of edge-to-edge, label-switched paths (LSPs) across many networks  has presented scaling challenges.  In particular, emerging business demands related to Carrier Supporting Carrier (CSC), global growth of IPv6 traffic, and delivery of services over native IPv4 networks require pertinent and flexible solutions. Many organizations prefer to continue with the existing MPLS-based solutions to more recent overlay technologies such as VXLAN.   A solution that solves these potential...
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NAT for an IP shared over BGP inside a VRF

Hi, I am having a bit of an issue in getting this to work and if anyone could help it would be greatly appreciated. I am trying to do a 1:1 Source and Destination NAT for a route advertised over BGP. The SNAT rule is working but the DNAT is not. Traffic hits the external interface but never exits the internal interface.   Thanks for taking a look!   Here is the relevant sanitized config: ! device: SSP2 (DCS-7150S-52-CL, EOS-4.17.0F) ! ! boot system flash:/EOS-4.17.0F.swi ! vlan 105 name Peer ! vlan 505 name Peer_TR ! vrf definition Peer_vrf rd...
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AS Ranges for Dynamic BGP Peer Groups

BGP neighbors, or peers, are initiated by configuration commands that cause BGP to establish TCP connections with other BGP speakers.  Dynamic neighbors are established by creating a listen range and accepting incoming connections from neighbors within that address range.  Dynamic neighbors must be configured using a dynamic peer group, which defines attributes for all neighbors associated with the listen range.  A BGP listen range has so far allowed exactly 1 remote AS number to be specified for acceptable incoming connections. The AS Ranges for Dynamic Peer Groups feature introduces a flexible means of specifying multiple, allowable remote AS numbers for...
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BGP AS path prepend using “last-as” keyword

The “set as-path prepend” clause in route-map configuration mode has been enhanced with the addition of the “last-as” keyword, which will prepend the AS path with the specified number of instances of the last AS number in the AS path. Currently, the command only accepts an explicit list of AS numbers to prepend to the AS path. This list may also include one or more “auto” keywords in place of AS numbers, which are replaced by the peer AS number for inbound routes, and the local AS number for outbound routes. By extending some AS paths, this feature enables customers...
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as masquerading – need to ibgp peer in a vrf using different as number than main vrf

I know with arista all VRF’s have to have the same AS number. lets say I use as 65000 to ebgp peer with someone. If I set up aanother VRF and want to ibgp peer with someone using as 65005, with the “local as” function where you impersonate an AS number, if I use local-as 65005 and peer with another router using 65005 will it behave as iBGP? Because I have an arista router using 65000 for eBGP with a partner and I need to also iBGP with someone using 65005 in a second VRF. Will this local-as approach work?...
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Load Balancing with ECMP: Hardware Configuration Lookup

Abstract: This publication illustrates a technique which can be used to find exactly how Arista devices program routes to send traffic across multiple available paths. An example will be given on the Arista DCS-7150S-52-CL-R running EOS version 4.14.8M. Initial configuration: As an IGP we are using OSPF with maximum paths feature configured: Arista(config)#router ospf 1 Arista(config-router-ospf)#maximum-paths 32 There are two iBGP peers configured via a peer-group “pg1”: Arista(config)#router bgp 65001 Arista(config-router-bgp)#neighbor pg1 maximum-routes 16000 Arista(config-router-bgp)#neighbor 172.20.18.49 peer-group pg1 Arista(config-router-bgp)#neighbor 172.20.18.121 peer-group pg1 iBGP advertisements: * >   10.82.2.32/27       172.20.16.143    0       100     0       64920 64944...
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